Ice cream shops in the Shiite stronghold of Kadhimiya are flush with sweet-toothed customers. Hospitals have new supplies. Rents have tripled as displaced Shiites flock to the historic district’s spacious homes, while pilgrims stream to the golden-domed shrine at its heart.

Here on the volatile Sunni-dominated west bank of the Tigris River, religious Shiite leaders and their militias have unquestionably consolidated control, transforming Kadhimiya into what could be a model for much of Baghdad if the Shiites have their way.

“This experience in Kadhimiya, you might find it in the future in every neighborhood throughout Iraq (http://topics.nytimes.com/top/news/international/countriesandterritories/iraq/index.html?inline=nyt-geo),” said Sheik Muhammad Bakr Khamis al-Suhail, the white-robed leader of the neighborhood council.

But the future that Kadhimiya points to may not be democratic, inclusive or just, at least by Western standards. Residents and American commanders describe the area as a nerve center for benign and malignant elements of Shiite power, the raw embodiment of the Shiite revival that has swept Iraq in the last four years.

It is a place, they say, where militia leaders, Iraqi politicians, criminals and clerics intersect and compete; a place where the Iraqi soldier protecting residents on Monday may be collecting bribes for a militia on Tuesday, praying at the mosque on Friday and firing at American troops over the weekend ...